So much flipping. Once I played a cultural game and I had a Chinese city in between my two cultural centers. During the expansion phase I had a gap in my borders as I tried to take resources. It descended to 1 population after losing all workable tiles, spent many turns at 99% of my culture but did not flip until the end of the game. It had only 3 units in the garrison. Another city was the one captured by Mao when Dogpiling Shaka, I controlled the nearby former Zulu cities and spammed culture there too, but Mao had his SoD of over 80 units in that city so no wonder it did not flip.